Ivory can cost more than gold on the black market, but the U.S. hopes to 'send a very clear signal' that it's only valuable when attached to a living elephant.

In a message to poachers and traffickers around the world, the U.S. crushed 6 tons of illegal elephant ivory Thursday. The confiscated tusks and trinkets — which came from at least 2,000 different elephants — were part of an ivory stockpile dating back to the 1980s.

The U.S. had never conducted a large-scale ivory crush before, but was prompted to act by a recent surge in elephant poaching. Roughly 30,000 elephants were killed by poachers in 2012, the highest total since the international community banned ivory trading in 1989. At that pace, experts say central Africa could be devoid of wild elephants in a decade.

"We want to send a clear message that the United States will not tolerate ivory trafficking and the toll it is taking on elephant populations, particularly in Africa," the Fish and Wildlife Service (FWS) says in a statement. "Destroying this ivory tells criminals who engage in poaching and trafficking that the United States will take all available measures to disrupt and prosecute those who prey on and profit from the deaths of these magnificent animals."

Africa's elephant population has plummeted by about 90 percent in the last 70 years, but stopping poachers isn't just about saving wildlife. The ivory trade is widely thought to help fund international crime syndicates and even terrorist groups like al-Shabaab, a Somali al-Qaeda affiliate that recently launched a brutal attack in Kenya. On Wednesday, U.S. Secretary of State John Kerry offered a $1 million reward for information leading to the breakup of the Xaysavang Network, a Laos-based group that "facilitates the killing of endangered elephants, rhinos and other species for products such as ivory."

The illegal ivory trade is now a $10 billion global industry, the FWS estimates, fueled largely by China's growing demand for tchotchkes carved from elephant tusks. But that's just part of the problem — the U.S. is the world's second-largest retail market for ivory, according to the International Fund for Animal Welfare, behind only China. U.S. inspectors seized at least 1,165 ivory specimens between 2009 and 2012, which may represent as little as 10 percent of the actual amount circulating around the country.

"The United States is part of the problem, because much of the world's trade in wild animal and plant species — both legal and illegal – is driven by U.S. consumers or passes through our ports," FWS Director Dan Ashe said Thursday. "We have to be part of the solution."

Complicating matters is that some ivory is legal in the U.S., such as items imported before the '80s, and it's hard to distinguish from contraband. The federal stash of confiscated ivory can't legally be sold, but the FWS says any sale would be counterproductive anyway. "Our criminal investigations and anti-smuggling efforts have clearly shown that legal ivory trade can serve as a cover for illegal trade," the agency explains. "Therefore, selling the ivory stockpile and allowing it to enter the marketplace could contribute to increased elephant poaching and stimulate even more consumer demand for ivory."

Some critics argue destroying the ivory just boosts demand by making it an even rarer commodity. The FWS dismisses that idea, however, pointing out its stockpile has been separate from the global supply ever since it was confiscated.

"This ivory would never be made available to the market," the FWS says in a fact sheet about the crush. "Its destruction has no impact on the overall supply and does not create any incentive for poaching. By demonstrating our commitment to combat poaching and illegal trade, and to arrest and prosecute people who engage in these activities, we are providing a strong disincentive to poachers and wildlife traffickers."

Other countries have also destroyed ivory reserves, perhaps most famously when Kenya burned 12 tons in 1989, drawing broad media coverage and helping spur the international ivory trade ban. Fire soon became a popular way to purge stockpiles, from Zambia's 1992 burning of 9.5 tons to Gabon's 5-ton blaze in 2012. Earlier this year, the Philippines used road equipment to crush 5 tons of ivory and then burned the remnants.

So why did the FWS decide against a fiery spectacle, especially if the goal is to intimidate criminals? A bonfire may be more dramatic, but it's apparently not a great way to get rid of ivory. Unless the fire stays extremely hot for long periods, it just chars the exterior and leaves the inside undamaged, according to National Geographic. Even in an 1,800-degree, oxygen-enriched propane fire, it might take months to thoroughly burn a single ton.

Following Thursday's crush — conducted by an industrial rock grinder at Colorado's Rocky Mountain Arsenal National Wildlife Refuge — the FWS still has a lot of pulverized ivory to deal with. The agency says it's working with the Association of Zoos and Aquariums "to develop a creative and informative use" of the crushed ivory, and FWS Director Dan Ashe announced at Thursday's ceremony that it will be used in educational displays.

Conservation groups widely praised the U.S. for destroying its stockpile and setting an example, although many are still pushing for stricter limits on any movement of ivory.

"Right now, Africa is hemorrhaging elephants," African Wildlife Foundation CEO Patrick Bergin said this week in a statement praising the U.S. decision to crush its confiscated ivory. "The only way to stanch the movement of illegal ivory is to wipe out the demand, and that begins with destroying stockpiles and stopping trade."